There has been a startling increase in the estimated world population of western lowland gorillas, a critically endangered species. A new census by the Wildlife Conservation Society has found more than 125,000 of the secretive great apes in the northern part of the Republic of Congo. To put that figure in perspective, the entire population of western lowland gorillas across seven Central African countries was estimated at fewer than 100,000 animals in the 1980s, and conservationists believed that number had been halved because of hunting and disease.

Researchers from the Bronx Zoo-based WCS, working in close cooperation with the Republic of Congo government, combed rainforests and isolated swamps in two adjacent areas covering 47,000 square kilometers, counting the "nests" that gorillas build from leaves and branches each night for sleeping. "These figures show that the northern Republic of Congo contains the mother lode of gorillas," said WCS president Steven Sanderson. The population density in one particularly rich forest patch was estimated at eight individuals per square kilometer.

WCS scientists say that the high numbers of gorillas in the region are due to successful long-term conservation management of the Republic of Congo's protected areas along with the remoteness and inaccessibility of key locations and food-rich swamp and open-canopy forest habitat. While many of the gorillas were found outside reserves, the government is committed to creating a new national park in the region, WCS notes. Gorillas across Central Africa are threated by commercial bushmeat hunting and the spread of the Ebola virus, fatal to apes as well as humans.